Electronic thermostat having high and low voltage control capability

Abstract

An electronic thermostat having high and low voltage control capability and varied functional capabilities. The thermostat is particularly suited for use with fan coil heating and cooling units. Specifically the thermostat uses relays to actuate external devices such as heating and cooling equipment, fans and dampers. The use of relays permits control voltages for these external devices to be different (e.g. 24 VAC, 208-230 VAC or 277 VAC).

What is claimed is: 
     
       1. A thermostat for controlling heating and cooling equipment of the type which includes a fan and at least one end device consisting of at least one heating and cooling fluid control valve, at least one electric heating apparatus and at least one air damper, said thermostat comprising: a base portion adapted to be mounted to a mounting surface;   a cover portion adapted to be attached to said base portion;   switch means for controlling the operation of the thermostat, said switch means being associated with said cover portion and being accessible for operation;   temperature setting means associated with said cover portion for setting a nominal temperature set point;   processing means being connected to one of said base and cover portions for receiving operating status signals and temperature indicating signals and for selectively generating output signals for controlling the heating and cooling equipment;   a first means for sensing the temperature of the air of a space in which the thermostat is to control;   a plurality of first connection means for connecting high voltage circuits associated with selected end devices;   a plurality of second connection means for connecting low voltage circuits associated with selected end devices;   said first connection means and said second connection means being separated from one another, said base portion being adapted to be attached to a conventional electrical box having a partition separating approximately one half of the interior from the other side thereof, each side being adapted to receive one of high voltage circuits and low voltage circuits, said partition separating said high voltage circuits from said low voltage circuits.   
     
     
       2. A thermostat as defined in claim 1 wherein said switch means further comprises: a fan switch for controlling the operating speed of the fan;   a mode switch for selecting the operating mode of the thermostat.   
     
     
       3. A thermostat as defined in claim 1 wherein said temperature setting means comprises an adjustable set point potentiometer that has an operating means that is manually accessible from outside of the cover portion by an operator. 
     
     
       4. A thermostat as defined in claim 1 wherein said first and second connection means are attached to said base portion, each of said first connection means being located at a first end portion and each of said second connection means being located at a second end portion opposite said first end portion. 
     
     
       5. A thermostat as defined in claim 1 wherein said high voltage circuits have voltage levels within the range of approximately 110 volts AC to approximately 277 volts AC. 
     
     
       6. A thermostat as defined in claim 1 wherein said low voltage circuits have voltage levels below approximately 30 VAC. 
     
     
       7. A thermostat as defined in claim 1 wherein said first temperature sensing means is located in said cover portion, said cover portion having a plurality of openings adapted to admit air inside said cover portion. 
     
     
       8. A thermostat as defined in claim 1 further including signals that are indicative of sensed temperature from a remotely located temperature sensing means. 
     
     
       9. A thermostat as defined in claim 1 wherein said first temperature sensing means comprises a thermistor. 
     
     
       10. A thermostat as defined in claim 4 wherein said first and second end portions have a center space therebetween adapted to receive large components located in said cover portion. 
     
     
       11. A thermostat as defined in claim 2 further including at least one relay means for controlling one of said end devices, said relay means producing a selectively switched output signal of up to approximately 277 VAC. 
     
     
       12. A thermostat as defined in claim 11 further including a printed circuit board mounted to the inside of said cover portion, said processing means being mounted to said printed circuit board. 
     
     
       13. A thermostat as defined in claim 12 further characterized in that said relay means is mounted to said printed circuit board. 
     
     
       14. A thermostat as defined in claim 11 further including a plurality third connection means for connecting a plurality of circuit termination of said printed circuit board to said first and second connection means. 
     
     
       15. A thermostat as defined in claim 14 wherein each of said third connection means comprises posts which are electrically connected to one of said first and second connection means when said cover portion is attached to said base portion. 
     
     
       16. A thermostat as defined in claim 11 further characterized in that said fan switch and said mode switch are mounted on said printed circuit board, said fan and mode switches being multiple position switches having operating means which extend through apertures in said cover portion, so that an operator can change switch positions without removing said cover portion.